Door opening mechanism



May 20, 1941. HASLAM 2,242,647

DOOR OPENING MECHANI SM Filed No a, 1938 s Sheets-Sheet i I 1N VENTOR.ROBERT IVA-SLAM ATTORNEYS.

May 20, 1941.

R. HAsLAM DOOR OPENING MECHANISM 6 Sheets-Sheet 2 Filed Nov. 8, 1958INVENTOR ROBERT HASLAM ATTORNEYS.

May 20, 1941.

R. HASLAM DOOR OPENING MECHANISM Filed Nov. 8, 1958 6 Sheets-Sheet '3ATTORNEYS.

May 20, 1941. R. HAs'LAM noon OPENING MECHANISM Filed Nov. 8, 1938 6Sheets-Sheet 4 INVENTOR. X03512? HAsLAM ATTORNEYS;

May 20, 1941. R HASLAM noon OPENING MECHANISM 6 Sheets-Sheet 5 FiledNov. 8

INVENTOR. HAsLAM 7 ATTORNEYS.-

May20, 1941. R. HASLAM DOOR OPENING MECHANISM 6 Sheets-Sheet 6 FiledNov. 8, 1938 1 w A m T m Camp m Mme Patented May 26, 1941 UNETED STATESFATE.

orrics 12 Claims.

This invention relates. to door opening mechanisms. It has for itsobjects the production of a device of this class which will be positivein its operation both in opening and closing the door and which willnevertheless be comparatively sim le in structure.

For the purpose of illustrating my invention, I have disclosed in thedrawings which form a part hereof, and will now describe two of the manypossible embodiments of my invention.

In said drawings,

Figure 1 is a perspective view of my novel structure attached to a door.A portion of the tread-plate 6 has been broken away for the purpose ofshowing otherwise hidden parts. The full lines show the position of therespective elements when the door is closed and the dot and dash linesshow the position of the arm and cable when the door is opened.

Figure 2 is a. plan view of the door actuating portion of my novelmechanism with the casing removed, taken along the lines 2-2 of Figure1.

Figure 3 is a front View of the disclosure in Figure 2.

Figure 4 is an end View of the disclosure in Figure 2 taken along theline 44 of said figure.

Figure 5 is a plan View of the tread portion of my mechanism.

Figure 6 is a section taken along the line 6--6 of Figure 5.

Figure '7 is a section taken along the line 7-1 of Figure 5.

Figure 8 is a section of a fragment taken along the line 8-8 of Figure5.

Figure 9 is a section of a fragment taken along the line 99 of Figure 5.

Figure 10 is a section of a fragment taken along the line |0|9 of Figure5.

Figure 11 is a section of a fragment taken along the line I Il l ofFigure 5.

Figures 12 and 13 are schematic plan views of the door actuating portionof the mechanism taken along the line 2-2 of Figure 1. The full anddotted lines in Figure 12 show the respective positions of therespective elements when the door is closed, while the dot and dashlines in this figure show the positions to which these elements havemoved just after a person has stepped upon the tread-plate.

The full and dotted lines in Figure 13 show the positions of therespective elements of the door actuating mechanism when the door isfully opened, and the dot and dash lines in Figure 13 show the positionsto which these elements have moved just after a person has stepped ofi"the tread-plate. A portion of the door intermediate its ends has beenbroken away to permit the showing of the remaining parts on as large ascale as possible.

Figure 14 is a plan view of a modification of the door actuating portionof my mechanism with the casing removed.

Figure 15 is a front View taken along the line l5l5 of Figure 14:.

Figure 16 (see Sheet 2 of the drawings) is a section taken along theline i6l6 of Figure 2.

Figure 17 (see Sheet 4 of the drawings) is an enlarged section of afragment taken along the line I'i-ll of Figure 5. The full lines showthe positions which the pin and tread-plate occupy before thetread-plate has been adjusted, and the dot and dash lines show theposition which each of these elements assumes after the treadplate hasbeen adjusted.

Referring more particularly to the drawings wherein similar referencenumerals denote similar parts, reference numeral I denotes my dooropening device as a unit. The unit I consists of the tread portion 2,the transmitting portion 3, and the door actuating portion 4.

The tread portion 2 consists of a frame 5, a tread-plate 6 pivoted withreference to said frame at I, and an arm 8 which is actuated in ahorizontal plane about a pivot 9 by the movement of said tread-plate 6.

The frame 5 is rectangular in shape and comprises the walls If], H, l2,and I3. The walls Ii), ll, l2, and I3 have, respectively, the slopingouter surfaces l4, I5, I6, and. IT and the vertical surfaces [8, I9, 20,and 2i. The walls In, H, l2, and I3 have formed therein the apertures 22through which extend suitable bolts 23 which fasten the frame 5 to thefloor 24.

Each of the walls H and i3 (see Figures 5 and 1'7) has formed therein aninternally threaded aperture 26 which receives a suitably threaded pin2?. Each pin 21 terminates in a nonthreaded portion 28 which extendsinto and is received in a suitable bore 30 formed in the boss 29 whichis formed on the tread-plate 6. Each threaded pin 21 has mounted thereonnear the outer end thereof the washer 25 and the locknut 31. Thenon-threaded portion 28 of the pin 21 serves as a pivot 1 for thetread-plate 6. The

threaded pins 21 also serve as a means for laterally adjusting thetread-plate 6. The locknut 3| serves to lock the threaded pin 21 in anydesired position.

A shoe 32 is formed in each of the front corners of the frame 5. Eachshoe 32 has a recess 33 formed therein which serves as a seat for thelower end 38 of the spring 34. The upper end 55 of the spring contactsthe inner surface 31 of the tread-plate 5 and serves to keep thetreadplate in the raised or normal position shown in the drawings.

The wall I2 has a cut-out 88 formed therein centrally thereof whichreceives the arms 48 of the bearing plate 39. Each of the arms 48 hassuitable apertures formed therein through each of J which a screw 4Iextends. This screw 4I attaches the arms 48 of the bearing plate 39 tothe wall i2 of the frame 5.

The bearing plate 99 has formed therein the cut-out 42 through which aportion of the wedge 83 may extend when the tread-plate 6 movesdownwardly. A roller 44 is carried by the bearing plate 39 and ispositioned for contacting the surface of the wedge 43. The surface 48 ofthe wedge 43 contacts a roller 41 which is suitably positioned in thearm 8. The arm 8 also carries a roller 28 which is suitably positionedfor contacting the surface 58 of the wedge 49 which extends downwardlyfrom the under surface 31 of the tread-plate 6. The wedges 43 and 49 actas a couple to cause the arm 8 to rotate about its ivot 9 from its fullline position shown in Figure 1 towards its dot and dash line positionin said figure whenever force is exerted upon the tread-plate 6 in thedirection indicated by the arrow A in Figure 7.

The bearing plate 38 has attached thereto by means of suitable screwsthe bar I39, the lower surface of which rests upon the floor 24 therebyfurnishing additional support to the outer end of II the bearing plate89. This construction permits the plate 39 to be raised a distance abovethe floor 24 sufficient to permit the wedges 43 and 49 to be depressedto their lowest respective points without touching the floor. Ittherefore becomes unnecessary to either make depressions in or to outholes in the floor 29.

The bearing plate 59 has attached thereto by means of suitable rivetsthe arm I48 which in turn has threadably mounted therein the bolt 5I.

The end 52 of the bolt 5! contacts the face 53 of the arm 8 and acts asa stop to limit the motion of the arm 8 in the direction of the arrow Bin Figure 1.

The arm 8 has formed therein a series of 5;

threaded apertures 54 any one of which receives the bolt 55 whichextends through a suitable eye formed in the lower end of the cable 58and serves to attach the cable 58 to said arm 8.

The cable 59 extends from the arm 8 through T a suitable aperture 51formed in the wall I8 of the frame 5, around a pulley 58 mounted in thelower end of the hollow standard 59, up through the standard 59, arounda pulley 58 mounted in the upper end of the standard 59 and is con- Thebracket 84 not only serves as a point of attachment for the strap 83 butit also serves as a support for one of the ends 58 of the plate 85 whichserves as the bearing member of the door actuating portion 4. plate 55is attached to a bracket 68 which in The other end 61 of the turn hasattached thereto one of the ends 18 of a turnbuckle cable 69. The otherend H of the turnbuckle cable 89 is attached to a suitable hook 12imbedded in the lintel 13. The turnbuckle cable 59 makes it possible toreadily level off the door actuating portion 4 and to compensate forsagging which may occur from time to time either in the door frame orother elements of the building to which the door opening device may beattached.

The other of the ends 16 of the lever arm 14 is fixedly attached to theshaft 11 which is carried by the bearing plate 65. The shaft 11 also hasfixedly attached thereto the gear 18 which meshes with a gear 19 fixedlyattached to the shaft 8| which is also carried by the bearing plate 65.The shaft 8| has fixedly attached thereto the gear 88 which ispositioned below the gear 19. The gear 88 meshes with the rack 82. Therack 82 is carried by an arm 83 which in turn is fixedly attached to oneof the ends 85 of the cam band 84. The other of the ends 85 of the camband 84 is pivoted on a shaft 81 which is carried by the bearing plate55. The cam band 84 passes between the rollers 9| and 92 carried by thearms 89 and 98 of the lever 88. The lever 88 is pivoted on a suitableshaft 93 carried by the bearing plate 65 and, in addition to the arms 89and 98, also has the arm 94 which terminates in a socket member 95. Thissocket member 95 has formed therein a suitable bore which receives thepin 98 which extends downwardly from the collar 91. The collar 91encompasses the arm 99 of the lever 98 and is slidable thereon. Thelever 98 is pivoted at one of its ends I98 upon the shaft I8I carried bythe plate 85 and has depending therefrom near the other of its ends I82the socket pin I84. The end I82 of the lever 98 is forked and hasmounted therein the roller I83. The socket pin I84 has a suitable boreformed therein which receives the pin I86 which extends upwardly fromthe collar I85 which is slidably mounted on the bar I81. The bar I81 isattached at its ends I88 and I89 to the door H8 which is to be actuated.The bar I81 has fixedly attached thereto near its end I89 the collarIII. This collar serves as a bearing surface for one of the ends H3 ofthe spring I I2 which is also mounted on the bar I81. The other end I I4of the spring I I2 is attached to the collar I I5 which is slidablymounted on the bar I81. The collar I85 contacts the collar H5 at acertain point in the swing of the door from its closed to its openposition causing said collar to move and compress the spring l I2. Thisin turn serves as a retarder and shock absorber with reference to themovement of the door to said position.

The free end of the arm 98 of the lever 88 has attached thereto one ofthe ends I I1 of the shock absorbing unit H8. The other end II8 of theunit I I6 is pivoted on the pin H9 carried by the plate 65.

The cam band 84 has extending therefrom the arm I28, the hook I2I ofwhich serves as a point of attachment for the end I23 of the spring I22.The other end I24 of the spring I22 is attached to a hook I21 extendingfrom a post I28 carried by the tensioning block I25. The tensioningblock I25 is mounted in suitable channels formed in the angles I28--I28attached to the .plate 65 for movement in a horizontal plane. Thetensioning block I25 is held in any desired position in the slideway I29by the pressure of the bolt I38 which is rotatably mounted in a suitablebox I3I carried by the plate 65. The strength of the sprin I22 is suchthat it will overcome the inertia of the door Ill) against movement, thefrictional force of the door III] upon its hinges and the frictionalforces in the door actuating mechanisms 4, so that in the absence of acounter-acting force or forces which may be exerted upon the door H as aresult of a pull upon the cable 56 the force of the spring I 22 will besufiicient to cause the door III] to close and keep it closed. Wheneverit is desired to increase the force exerted by the spring I22 on the armI20 it is only necessary to advance the bolt I30 in the direction of thearrow Z in Figure 4.

It is to be noted that the first act in mounting the tread-plate in theframe 5 is the positioning of said tread-plate upon its pivots "I. Whenthis is accomplished it often happens that the wedge 43 is not in theposition shown in Figures 5 and 6 where the face 45 of said wedgecontacts the roller 44. Instead, this face is at a point either to theright or left of said roller. To properly position said wedge it is onlynecessary to advance the pins II in the direction and through thedistance which the wedge 43 must be moved in order to bring it to theposition shown in Figures 5 and 6. In the course of this motion one ofsaid pins will move outwardly, thereby removing its shoulder 545 as abarrier to the motion of said treadplate; and the shoulder I45 of theother of said pins will contact that face I55 of the tread-plate E whichis contiguous thereto, thereby pushing said tread plate 6 before it. Inthe course of said motion the tread-plate 6 carries with it the wedge 43which is finally caused to assume the position shown in Figures 5 and 6.The full and dot and dash lines in Figure 17 portray the respectivemovements of one of the pins and of the treadplate in the making of suchan adjustment.

In this case the wedge 43 fell between the rollers 14 and ll with theface 45 out of contact and to the right of the roller 44. To secure suchcontact it was therefore necessary to move the wedge towards the left.The threaded pin ll at the left side of the tread portion 2 wastherefore screwed outwardly (toward the left) and moved from its fullline position shown in Figure 17 to its dot and dash line position insaid figure. Thereafter, the threaded pin IT at the right side of thetread portion 2 was screwed inwardly (toward the left) a distance equalto that which the pin on the left side was moved outwardly. In thecourse of this motion, the shoulder I45 of the right hand pin contactedthe face I55 of the tread-plate 6 which was contiguous thereto andpushed the plate 6 toward the left from its position designated by thefull lines of the fragment shown in Figure 17 to that shown by the dotand dash lines in said figure. When the tread-plate reached the positiondesignated by the dot and dash lines in Figure 17 the wall contacted theroller 45.

It is further to be noted that the cable may develop some slackness inuse. Such slack is readily eliminated by advancing the bolt 5| thenecessary distance.

It is further to be noted that in assembling the the tube I46 whichtelescopes over the upper end of the shaft I45, and the tube Ml whichtelescopes over the lower end of the shaft I45. The tubes I55 and MI areeach laterally movable upon said shaft I45 and are also rotatablethereon. The tube I 36 carries the pulley 60 and is locked in thedesired position upon the shaft I45 by means of the set screw M8. Thetube I47 carries the pulley 53 and is locked. in the desired position bythe set screw I49.

Although the operation of my device is believed to be obvious from thedrawings and foregoing description, yet to obviate any possibility of amisiuiderstanding the following detailed description is here given.

Let it be assumed that the door III) is closed and that a person isdesirous of causing the same to open. As he moves toward the door I IIIhe steps upon the tread-plate 5. His weight exerts a force upon thetread-plate 6 in the direction of the arrow A in Figure 7, which isgreater than the force exerted by the spring I22 upon the cam band 84.As a result, the tread-plate 5'. moves downwardly about its pivots l andcarries the wedges 13 and G9 downwardly with it. In the downward motionof the wedge 43 its surface 45 contacts and exerts pressure upon theroller 41 and in the downward motion of the wedge 49 its surface 50contacts the roller 58. This results in the action of a couple upon thearm 8 causing it to move from its full line position in Figure 1 to itsdot and dash line position in said figure. This results in the movementof the cable 56 which in turn causes the lever arm 15 to move in thedirection of the arrow C in Figures 2 and 12. This results in themovement of the gear 18 in the direction of. the arrow D, of the gear ISin the direction of the arrow E, of the gear in the direction of thearrow F, of the rack 82 in the direction of the arrow G, of the band 84in the direction of the arrow H. At the beginning of this motion, therack 82 and the cam band 34 move from their respective full and dottedline positions in Figure 12 to their respective dot and dash linepositions in said figure. When the cam band 84 reaches its dot and dashline position in Figure 12, its surface I32 contacts and exerts pressureupon the roller 92 carried by the lever arm 95 urging the lever arm 98of the lever 88 in the direction of the arrow I. This results in therotation of the lever 88 about its pivot 53 in the direction of thearrow J This results in the movement of. the arm 94 of the lever 83 inthe direction of the arrow K. This motion is communicated to the collar91 through the socket 95 and the pin 96. This results in a contactbetween the side I35 of the lever arm 99 with that surface of the collar91 adjacent to said side. This results in a pressure upon the lever arm99 in the direction of the arrow L. This causes the rotation of thelever 38 about its pivot IIFI in the direction of the arrow M. In movingin the direction of the arrow L, the arm 99 carries with it the socketpin I64. The socket pin I 04 communicates this motion to the collar I05through the pin I86. This causes the collar I05 to exert pressure uponthe side I36 of the bar I01 in the direction of the arrow N. This inturn causes the door I III to open by rotating in the direction of thearrow 0 about its hinges I38. As the door IIB continues to open, thecollar I05 contacts the collar H5 and causes it to move in the directionof the arrow P which in turn causes the spring II 2 to becomecompressed. The spring IIZ acts as a shock absorber and also as aretarder to slow down and limit the motion of the door IIU.

When the person steps off the tread-plate 6, the force which he exertedin the direction of the arrow A (Figure 7) is removed. The pull of theextended spring I22 then becomes the strongest force in the dooractuating mechanism 4. As a result, all of the movements hereinabovespecified are reversed and the door I I8 caused to close. In doing so,the cam band 84 and its associated elements move from their respectivefull line positions shown in Figure 13 to their respective full linepositions shown in Figure 12, and the cable 55 and arm 8 move from theirrespective dot and dash line positions in Figure 1 to their respectivefull line positions in said figure. This permits the springs to forcethe tread-plate 6 to rotate about its hinges I and rise from itsdepressed position to its normal position shown in Figures 1 and '7 ofthe drawings.

In the first phase of the movements aforesaid, the cam band 84 movesfrom its full line position shown in Figure 13 to its dot and dash lineposition in said Figure 6. In doing so, the outer face I32 of the camband 84 ceases to contact the roller 92 carried on the lever arm 95while the inner face I33 of said cam band 84 comes into contact with theroller 9! carried by the lever arm 89. This removes the pressure on thelever 88 causing it to rotate in the direction of the arrow J in Figure2 and results in a pressure upon the lever 88 causing it to rotate inthe direction of the arrow Q in Figure 13. This in turn results in themovement of the lever arm 94 in the direction opposite to the arrow K.

This motion is communicated to the collar 91 and results in a contactbetween the side I35 of the lever arm 39 and that surface of the collar32' adjacent to said face. This results in a pressure upon the lever arm99 in a direction opposite to the arrow L. This causes the rotation ofthe lever 98 about its pivot IIlI in the direction of the arrow R inFigure 13. In the course of this rotation, the lever arm Q9 carries withit the socket pin Hi4 which communicates its motion to the collar H15.This causes the collar I05 to exert pressure upon the side I3! of thebar II)? in a direction opposite to the arrow N. This in turn causes thedoor I iii to close by moving about its hinges I353 in the directionopposite to the arrow 0. It is to be noted that at certain points duringthe opening and closing of the door IIB, the roller I83 comes into aposition where it contacts the door I III. During the motion of closingthe door, this contact produces a force on the door I ID in thedirection of the arrow N. In the act of closing the door I I0, thiscontact does not result in any appreciable force which retards themotion of the door I I8 to its closed position. This is because thelever 99 is constantly being urged in the direction opposite to thearrow N during the time that the door I I9 is being closed.

While the cam band 84 is exerting the pressure upon the roller 9! whichresults in the closing of the door IIfl, the rack 83 moves in thedirection of the arrow S shown in Figure 13. This results in motions inthe gears 80, I9, and I8 in the lever I l, and in the cable 56 in thedirection of the arrows T, U, V, W, and X, respectively. This results ina pull upon the arm 9 causing it to move from its dot and dash lineposition to that shown by the full lines in said figure. This is readilyaccomplished because the springs 3 have already caused the tread-plate 6to return from the depressed position to its normal position.

The door actuating portion I4I shown in Figures 14 and 15 difiers fromthe door actuating mechanism 4 shown in Figures 1 to land 12, 13 and 16only in the following particulars:

(1) The gears 19 and have been eliminated.

(2) The rack I42 has been substituted for its equivalent, 83. I

(3) The rack I42 meshes directly with the gear I43 which otherwise isthe equivalent of the gear I8.

(4) The lever I44 has been substituted for its equivalent, the lever 14.

(5) The tube I46 of the hollow standard 59 has been rotated from theposition shown in Figures 1 and 2 to that shown in Figure 14. In thecourse of this rotation, the tube I46 has carried the pulley 60 from itsposition shown in Figures 1 and 2 to that shown in Figure 14.

The door actuating portion I4I may be substituted in my novel mechanismfor the door actuating portion 4, particularly in cases where the doorIII) is comparatively light. With the exception of the fact that thereis a direct contact between the rack I42 and the gear I43 and thereforea direct transfer of force from each of said elements to the other, theunit which has a door actuating portion I4I as a component partfunctions exactly in the, same manner as the unit which has a dooractuating portion 4 as a component part.

The foregoing description is to be understood as being by the way ofillustration only and not by the way of limitation since many changesmay be made in the disclosure here made without departing from thespirit of my invention. These changes may include, among other things,changes in the shape and size of the various component elements of mymechanism and changes in the material of which said elements are made.

Having described my invention, what I claim as new and useful is:

1. A door opening device consisting of a base member; a tread-platepivotally mounted in said base member; a door actuating portionpositioned for operative contact with the door which is to be opened bysaid door opening device, said door actuating portion comprising a barcarried by said door, sliding means mounted for movement upon said bar,an arm. pivoted near one of its ends and attached to said sliding meansnear the other of its ends, sliding means mounted for .movement uponsaid arm, a second arm pivoted by said second arm, a cam band pivotednear one of its ends and positioned for contacting one of said camcontacting surfaces and exerting a force upon said bar mounted slidingmeans in the direction necessary to open said door when a person stepsupon said tread-plate, and for contacting the other of said camcontacting surfaces and exerting a force upon said bar mounted slidingmeans in the direction necessary to close said door when said personsteps off said tread-plate; and means operatively connecting said camband with said tread-plate.

2. A door opening device consisting of a base member; a tread-platepivotally mounted in said base member; a door actuating portionpositioned for operative contact with the door which is to be opened bysaid door opening device, said door actuating portion comprising a barcarried by said door, sliding means mounted for movement upon said bar,an arm pivoted near one of its ends and attached to said bar mountedsliding means at the other of its ends, sliding means mounted formovement upon said arm, a second arm pivoted intermediate its ends andattached to said arm mounted sliding means near one of its ends, twospaced apart cam contacting surfaces positioned upon said second armintermediate its pivot point and its free end, a cam band pivoted nearone of its ends and positioned intermediate said cam contacting surfacesfor contacting one of said cam contacting surfaces and exerting a forceupon said bar mounted sliding means in the direction necessary to opensaid door when a person steps upon said tread-plate and for exerting aforce upon said bar mounted sliding means in the direction necessary toclose said door when said person steps off said treadplate; and meansoperatively connecting said cam band with said tread-plate.

3. A door opening device consisting of a base member; a tread-platepivotally mounted in said base member and movable therein to assumeeither a raised or a lowered position; an arm mounted for movementbeneath said tread-plate; means carried by said tread-plate andpositioned for contacting said arm and exerting a force on said arm whensaid tread-plate is being moved toward its lowered position; a dooractuating portion positioned for operative contact with the door whichis to be opened by said door opening device, said door actuating portioncomprising a bar carried by said door, sliding means mounted formovement upon said bar, an arm pivoted near one of its ends and attachedto said bar mounted sliding means at the other of its ends, slidingmeans mounted for movement upon said arm, a second arm pivotedintermediate its ends and attached near one of its ends to said armmounted sliding means, two spaced apart cam contacting surfacespositioned upon said second 'arm intermediate its pivot point and itsfree end,

said tread-plate and for exerting a force upon plate with said cam band.

4. A door opening device consisting of a base member; a tread-platemounted in said base member and movable therein to either a raised orlowered position; resilient means positioned in said base member,contacting said tread-plate and exerting a force on said tread-platesufficient to hold said tread-plate in its raised posi tion; an armpivoted intermediate its ends and positioned beneath said tread-plate; aWedge carried by said tread-plate and positioned for contacting one ofthe faces of said arm; a second wedge carried by said tread-plate andpositioned for contacting that face of said arm opposite to that whichis contacted by the first of said wedges and on that side of the pivotpoint which is opposite to that which is contacted by the first of saidwedges; a door actuating portion positioned for operative contact withthe door which is to be opened by said door opening device, said dooractuating portion comprising a bar carried by said door, sliding meansmounted for movement upon said bar, a base plate, an arm pivoted nearone of its ends in said base plate and attached to said bar mountedsliding means at the other of its ends, sliding means mounted formovement upon said arm, a second arm pivoted intermediate its ends insaid base plate and attached near one of its ends to said arm mountedsliding means, two spaced apart cam contacting surfaces positioned uponsaid second arm intermediate its pivot point and its free end, a camband pivoted near one of its ends and positioned intermediate said camcontacting surfaces for alternately contacting each of said camcontacting surfaces, means attached to said cam band for exerting aforce on said cam band in the direction necessary to cause said cam bandto contact one of said cam contacting surfaces and to exert a force uponsaid bar mounted sliding means in the direction necessary to close saiddoor, and a second means operatively connecting said cam band with saidarm positioned beneath said tread-plate for exerting a force on said camband in the direction necessary to cause said cam band to contact theother of said cam contacting surfaces and exert a pressure upon said barmounted sliding means in the direction necessary to open said door whena person steps upon said tread-plate.

5. A door opening device comprising means mounted for sliding movementupon the door which is to be opened; an arm pivoted at a pointintermediate its ends; means operatively connecting' said pivoted armwith said sliding means; a pair of spaced apart cam contacting surfacespivotally mounted on said arm; a cam band pivoted near one of its endsand extending between said cam contacting surfaces; cam band actuatingmeans operatively connected with said cam band for exerting a force uponsaid cam band in the direction necessary to cause said cam band tocontact one of said cam contacting surfaces and exert a force upon saiddoor mounted sliding means in the direction necessary to open said door;and a second cam band actuating means operatively connected with saidcam band and exerting a force upon said cam band in the directionnecessary to cause said cam band to contact the other of said camcontacting surfaces and exert a force upon said door mounted slidingmeans in the direction necessary to close said door.

6. A door opening device comprising a bar carried by the door which isto be opened; sliding means mounted for movement upon said bar; asupporting member; an arm pivoted near one of its ends in saidsupporting member and attached to said sliding means near the other ofits ends; sliding means mounted for movement upon said arm; a second armpivoted intermediate its ends in said supporting member and attached tosaid arm carried sliding means near one of its ends; a pair of spacedapart cam contacting members carried by said second arm; a cam bandpivotally mounted in said supporting member and extending between saidcam contacting surfaces; cam band actuating means operatively. connectedwith said cam band for exerting a force upon said cam band in thedirection necessary to cause said cam band to contact one of said camcontacting surfaces and exert a force upon said door mounted slidingmeans in the direction neces-- sary to open said door; and a second camband actuating means operatively connected with said cam band andexerting a force upon said cam band in the direction necessary to causesaid cam band to contact the other of said cam contacting surfaces andexert a force upon said door mounted sliding means in the directionnecessary to close said door.

'7. A door opening device: comprising means mounted upon the door whichis to be opened for alternately exerting a force upon said door eitherin the direction necessary to open or in the direction necessary toclose said door; an arm pivoted at a point intermediate its ends; meansoperatively connecting said ivoted arm with said door mounted means; apair of spaced apart cam contacting surfaces pivotally mounted on saidarm; a pivotally mounted cam band extending between said cam contactingsurfaces; cam band actuating means operatively connected with said camband for exerting a force upon said cam band in the direction necessaryto cause said cam band to contact one of said cam contacting surfacesand exert a force upon said door mounted means in the directionnecessary to open said door; and a second cam band actuating meansoperatively connected with said cam band and exerting a force upon saidcam band in the direction necessary to cause said cam band to contactthe other of said cam contacting surfaces and exert a force upon saiddoor mounted means in the direction necessary to close said door.

8. An element of an automatic door opening device, said elementcomprising sliding means which is attached to the door which is to beopened; a supporting member; an arm pivoted near one of its ends in saidsupporting member and attached to said sliding means near the other ofits ends; sliding means mounted for movement upon said arm; a second armpivoted intermediate its ends in said supporting member and attached tosaid arm carried sliding means near one of its ends; a pair of spacedapart cam contacting members carried by said second arm; a cam bandpivotally mounted in said supporting member and extending between saidcam contacting surfaces; cam band actuating means operatively connectedwith said cam band and exerting a force upon said cam band in thedirection necessary to cause said cam band to contact one of said camcontacting surfaces and exert a force upon said sliding means in thedirection necessary to close said door; and means operatively connectedto said cam band for connecting said cam band to a source of power.

9. A door opening device comprising a base member; a tread platepivotally mounted in said base member; a door actuating portionpositioned for operative contact with the door which is to be opened bysaid door opening device, said door actuating portion comprising a barwhich is connected to said door, sliding means mounted upon said bar, apair of spaced apart cam contacting members operatively connected tosaid sliding means, a cam band extending between said cam contactingmembers and positioned for contacting one of said cam contacting membersand exerting a force upon said sliding means and cause said slidingmeans to mov in the direction necessary to open said door when a personsteps upon said tread plate and for exerting a force upon said slidingmeans and cause said sliding means to move in the direction necessary toclose said door when said person steps off said tread plate; and meansoperatively connecting said cam band with said tread plate.

10. A door opening device comprising a base member; a tread platemovably mounted in said base member; a door actuating portion positionedfor operative contact with the door which is to be opened by said dooropening device, said door actuating portion comprising a bar which isconnected to said door, sliding means mounted upon said bar, an armoperatively connected to said sliding means, a second arm operativelyconnected to said first arm, a pair of spaced apart cam contactingmembers carried by said second arm, a cam band extending between saidcam contacting members and positioned for contacting one of said camcontacting members and exerting ;a force upon said sliding means throughsaid second and first arms and cause said sliding means to move in thedirection necessary to open said door when a person steps upon saidtread plate, and for contacting the other of said cam contacting membersand exerting a force upon said sliding means through said second andfirst arms and cause said sliding means to move in the directionnecessary to close said. door when a person steps off said tread plate;and means operatively connecting said cam band with said tread plate.

11. An element of an automatic door opening device, said elementcomprising sliding means which is attached to the door which is to beopened; a supporting member; an arm pivoted in said supporting member ata point intermediate its ends; a pair of spaced apart cam contactingmembers pivotally mounted in said arm; means operatively connecting saidarm with said sliding means; a cam band pivotally mounted in saidsupporting member and extending between said cam contacting surfaces;cam band actuating means operatively connected with said cam band andexerting a force upon said cam band in the direction necessary to causesaid cam band to contact one of said cam contacting surfaces and exert aforce upon said sliding means in the direction necessary to close saiddoor; and means operatively connected to said cam band for connectingsaid cam band to a sourc of power.

12. An element of an automatic door opening device, said elementcomprising means mounted upon the door which is to be opened foralternately exerting a force upon said door either in the directionnecessary to open or in the direction necessary to close said door; asupporting member; an arm pivoted in said supporting memher at a pointintermediate its ends; apair of spaced apart cam contacting memberspivotally mounted in said arm; means operatively connecting said armwith said door mounted means; a cam band pivotally mounted in saidsupporting member and extending between said cam contacting surfaces;cam band actuating means operatively connected with said cam band andexerting a force upon said cam band in the direction necessary to causesaid cam band to contact one of said cam contacting surfaces and exert aforce upon said door mounted means in the direction necessary to closesaid door; and means operatively connected to said cam band forconnecting said cam band to a source of power.

ROBERT HASLAM.

